Waterproofing material



United States Patent O 3,497,417 WATERPROUFING MATERIAL Anthony R. Rizzo, Lynn, Mass., assignor to AFCO Products Inc., Cambridge, Mass., a corporation of Massachusetts Filed Dec. 29, 1964, Ser. No. 421,936 Int. Cl. B32b 15/04, 15/20, 1]/08 U.S. Cl. 161-224 10 Claims ABSTRACT OF THE DISCLOSURE This invention relates to waterproofing materials and, more particularly, to waterproong materials having a novel bimetallic core.

For a great many years, materials containing sheet copper as a component have found widespread use in the construction field for waterproofing materials such as flashing and the like. Copper has been a particularly desirable material for such purpose because it is one of the least chemically active of the commercial metals, it is highly resistant to corrosion from air, water and to weak atmospheric acid solutions, and is highly resistant to acids and alkalies which may be present in concrete or mortar. In addition, copper has high tensile strength and great puncture resistance.

The dependability of the copper insofar as these characteristics are concerned, however, is directly dependent upon the thickness of the metal. In exposed flashing, the thickness of the metal is generally 16 oz. and in the conventional through-wall ilashings, metal thicknesses reaching from l oz. to 7 oz. per square foot of metal weight have been successfully used provided, however, that the lighter the metal weight the more it must be protected (on one or both sides) by either a complementary metal or other durable materials to give the relatively thin copper protection from puncture, abrasion, sculiing at time of installation and to provide permeability during its lifetime.

In more recent years, laminated ilashing materials containing both copper and lead lamina have come into use in conventional throughwall flashing applications. In flashing materials of this type, the copper provides the unique characteristics outlined above and the lead portion of the flashing material provides body and is almost indestructible by acids. When properly protected during the relatively short duration of the curing stage of mortar or concrete, the lead will also resist any alkalies which may be present in such building materials.

In prior art flashing materials utilizing a lead-copper composite, a variety of techniques have been utilized to secure the lead and copper lamina to one another. One such technique involved a hot dip process in which a sheet of copper is immersed in molten lead at a temperature of approximately 600 F. suiliciently to fully coat both sides of the copper sheet with a layer of lead. Such a technique presents many diculties, not the least signicant of which is the problem of obtaining a uniform coating of lead throughout the extent of the copper base sheet. To the extent that any thin spots are present in the lead coating, corrosion-susceptible areas are created which may lead to the early destruction of the ashing material.

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Additional diiiculties relating to this techniques involve the requirement for high temperatures involved in using molten metallic materials (these temperatures are high even if a lead alloy, such as a tin-lead material, is utilized), as well as the ditliculty of adhering the lead to the copper in a manner such as to preclude the possibility of their separation in use. A still further problem involved in this method is that it can be used on a practical basis only when it is desired to coat the copper base sheet on both of its sides with a lead covering. Finally, lead coated with copper in this manner has been deemed too expensive for use in conventional construction.

Another approach to the lead-copper composite iiash` ing material has involved the use of an asphaltic bonding material between sheets of lead and copper, such as is disclosed in Patents 2,695,854, 2,734,010 4and 2,748,043. Among the shortcomings of such materials is their significant susceptibility to delamination resulting from improper bonding.

In accordance with the present invention, it has now been discovered that all the advantages of the two complementary metals, copper and lead, can be obtained in composite tlashings (for both exposed and concealed applications) and other waterproofing without the attendant disadvantages possessed by prior art materials by utilizing a waterproofing material containing a core of lead electrodeposited on copper. It is accordingly a primary object of the present invention to provide novel waterprooiing materials having a core of lead electrodeposited on copper.

It is another important object of the present invention to provide improved waterproofing materials having lead electrodeposited on either one or both sides of a copper base sheet in which the uniformity of thickness of lead coating throughout the extent of the copper basaA sheet is extremely great and wherein the lead is rmly and securely bonded to the copper without the necessity for intermediate bonding agents.

These and other important objects and advantages of the present invention will become more apparent in connection with the ensuing description and claims, as well as the appended drawings wherein:

FIG. l is a view of one form of a novel waterproofing material of the present invention, partially broken away to more clearly illustrate the construction of this material;

FIGS. 2, 3 and 4 are views similar to that of FIG. 1 but illustrating alternative forms of waterproofing materials within the framework of the present invention.

At the outset of the following description of the novel waterproofing materials of the present invention, it would be helpful to discuss the nature and characteristics of the lead-copper bimetallic core used to fabricate said materials. The lead-copper core which is utilized in practicing the present invention is made by an electrolytic process in which a coating of lead is electrodeposited on one or both sides I(depending upon the nature of the product desired) of a sheet of copper. The sheet of base copper on which the lead is electrodeposited is preferably electrolytically formed, though it is within the contemplation of the present invention to electrodeposit the lead coating on rolled (wrought) copper sheeting. An electrolytic process by which the lead may be deposited on the copper sheeting is fully disclosed in the copending application 0f Charles E. Yates entitled Electrolytic Method and Apparatus and led in the U.S. Patent Oice on Dec. 24, 1964 under Ser. No. 421,048, now abandoned, whose disclosure is hereby incorporated by reference.

In forming the lead-copper core for conventional concealed flashing material use, the copper base sheet will ordinarily be comprised of l ounce copper foil (l ounce per square foot) whose thickness is .0014, though lighter or heavier copper base sheets may be utilized if desired.

For example, 1/2 ounce (.0007" thickness) copper sheeting may be used as the base upon which the lead is electrodeposited. Alternatively, the present invention makes possible the use of the same or heavier weights of the combined metals at no increase in co-st over conventional flashing materials containing a copper sheet of the same or heavier thickness. For example, heavier copper sheeting, i.e., up to about ounces per square foot (.014 thickness), may be utilized as the copper base sheet, with a deposit of lead on one or both sides of 8 ounces per square foot, thereby totalling 18 ounces per square foo of the combined metals.

As indicated, the lead coating may be electrodeposited on one or both sides of the base copper sheeting. While the thickness of lead coating may be varied througha wide range (in the case of the copper sheet coated on both sides with lead, the quantity of lead on one side may vary from that on the other side), the preferred lead deposits for use in the flashing materials of the present invention are 1, 2, 4 and 6 oz. per square foot of copper sheet, respectively.

Typical lead-copper coies for use in fiashing materials coming within the framework of the present invention have the following specifications:

Utilizing a lead-copper core such as has been described above, a great variety of flashing materials within the contemplation of the present invention may be fabricated. One such ashing material is illustrated in FIG. 1. The flashing material of FIG. 1 contains a lead-copper core illustrated generally at 10 and having a lead layer 12 and a copper layer 14. Bonded to the lead layer 12 by means of a suitable asphaltic material 16 is an asphalt-saturated cotton fabric 18, which has been dusted with .mica 20 to prevent sticking. The asphaltic material utilized may conveniently be laminating grade asphalt (170 type) or asphalt based, naphtha solvent, asbestos fibrated adhesive. The mica which is dusted on the cotton fabric 18 may conveniently be #60 grade dry ground mica flakes. Bonded to the exposed surface of the copper sheet 14 by means of an asphaltic composition 22 is an asphaltsaturated cotton fabric 24 which contains a mica coating 26 to prevent sticking. As will be seen, the materials on the lead side of the core are the same as those on the copper side of the core. The bimetal core weight for use in the structure of FIG. 1 may suitably be 2, 3, 5 or 7 oz. per square foot.

The structure of FIG. l may conveniently be prepared by applying an asphaltic coating of approximately $46 thickness to one side of each of the asphalt-saturated cotton fabric layers 18 and 24 and passing such cotton fabrics with their asphalt-coated sides in contact with the lead-copper core 10 through a laminating machine. Alternatively, the lead-copper core could be coated on both sides (as by immersing it in hot asphalt) to obtain the necessary bonding.

After the mica has been dusted on the outer surfaces of the structure of FIG. 1, the flashing material thus formed .may conveniently be passed through a crimping machine to impart crosswise corrugations 28 (shown in FIG. 1 by phantom lines, for ease of illustration) on the outer surfaces of the material. The preferred embodiment of this construction contains corrugations spaced about 1A apart.

In addition to being acid and alkali resistant, the structure of FIG. l provides an extremely flexible and rugged flashing product which is quite inexpensive to fabricate.

This material possesses excellent mortar bonding qualities as a result of the fabric laminate 18 and 24 and, through its crimping, provides for drainage and allows for expansion and contraction.

The structure of FIG. 2 contains a lead-copper core indicated generally at 30 and having a lead layer 32 electrodeposited on a copper sheet 34. Adjacent and in contact with the lead layer 32 is a fiberglass reinforcing cloth 36 (which may conveniently have 1/2 x 1/2 spacing, warp and fill) covering which is an asphaltic layer 38, by .means of which the fiberglass reinforcing cloth 36 is bonded to the lead layer 32. Coated on copper sheet 34 is a second asphalt layer 40. Asphaltic layers 38 and 40 which may be the same as those used in the construction of the fiashing material of FIG. 1) are each dusted with mica 42, as is clearly illustrated in FIG. 2.

The liashing material of FIG. 2 may conveniently be fabricated by passing the bimetallic core 30 and the fiberglass reinforcing cloth 36 into a dip tank of hot asphalt compound (which may suitably be maintained at 300 F.), the fiberglass reinforcing cloth and bimetallic core being subsequently passed through a laminating machine in contact with one another to form the desired lamination. Through the provision of suitable doctor blades outside of the dip tank, a coating of not less than 3 oz. per square foot of asphalt compound will be maintained on each side of the desired lamination. The mica dust 42 (preferably 320 mesh dry ground) is then applied to both sides of the finished sheet to prevent sticking. As was the case in connection with the structure of FIG. 1, the bimetal core weight preferred for use in the structure of FIG. 2 may be 2, 3, 5 or 7 oz. per square foot.

The structure of FIG. 2, which is somewhat less expensive to fabricate than that of FIG. 1, not only provides the long-lasting qualities possessed by all the copper-lead flashing materials of the present invention but additionally provides protection against electrolysis and green mortar by means of its rubbery asphaltic coating, which is effectively self-sealing. This ashing material is acid and alkali resistant and has increased strength resulting from the fiberglass reinforcement.

The structure of FIG. 3 contains a lead-copper core identified generally at 44 and which is comprised of a base copper sheet 46 and an electrodeposited lead coating 48. Bonded to the lead coating 48 by means of an asphaltic layer 50 is a fiberglass reinforcing cloth 52. Bonded to the fiberglass reinforcing cloth 52 by means of asphalt layer 54 is a sheet of primary crepe kraft paper 56. As illustrated in FIG. 3, the base copper sheet is exposed.

'Ihe lead-copper core of the structure of FIG. 3 is preferably either of the 2 or 3 oz. (per square foot) variety. The asphaltic bonding agent is preferably laminating grade asphalt type). The fiberglass reinforcing cloth 52 is preferably provided with Ms" x M3" spacing to the inch (warp and fill) and the kraft paper 56 is preferably 60 lb. (per ream) primary crepe kraft paper.

The fiashing material of FIG. 3 may conveniently be `made by applying hot asphalt to one side of kraft paper 56 or to the lead side of the bimetallic core 44 (or to both) and bringing the .paper and bimetal core into sandwiching contact with the fiberglass reinforcing cloth 52 in a conventional laminating machine, in which the three lamina 44, 52 and 56 are bonded together under pressure by means of the asphalt. About 60 pounds of asphalt per ream of kraft paper 56 is applied in each of asphalt layers 50 and 54.

The structure of FIG. 3 provides flashing material within the framework of the present invention in its most economical form. While providing the basic waterproofing qualities desired in a flashing material and while benefiting from the advantages obtained through the bimetallic leadcopper core of the present invention, this material is not as rugged in use as those of FIGS. l, 2 and 4 in light of its exposed copper layer. This lack of covering on the copper lamina, however, does result in decreased fabrication costs and makes the product lighter and thus easier to handle.

The structure of FIG. 4 contains a bimetallic core indicated generally at 58 and which is comprised of a base copper sheet 60 and an electrodeposited lead layer 62. On each side of the bimetallic core 58 are, in this sequence, a sheet of primary crepe kraft paper 64, a sheet of fiberglass reinforcing cloth 66 and a second sheet of primary crepe kraft paper 68. The sheets of kraft paper and fiberglass reinforcing cloth are bonded to one another and to the bimetallic core 58 by means of asphaltic layers 72, 74 and 76. The copper side of the fiashing material illustrated in FIG. 4 is similarly provided with a sheet of primary crepe kraft paper 78, fiberglass reinforcing cloth -80 and a second sheet of primary crepe kraft paper 82, said sheets being bonded to one another and to the bimetallic core 58 by means of asphaltic layers 84, 86 and 88.

Bimetallic core 58 may conveniently be of the 2, 3, 5 or 7 oz. per square foot variety. The primary crepe kraft paper is preferably asphalt impregnated, 60 1b. primary crepe kraft paper being suitable for this purpose. The fiberglass reinforcing cloths 66 and 80 are preferably of 1/2" x 1/2 spacing to the inch (warp and fill). Each of the asphaltic layers between lamina is applied in a quantity of about 70 lb. of asphalt per ream of kraft paper utilized.

The structure of FIG. 4 is preferably fabricated by means of a multi-step procedure. In a first step, the outer sandwich of primary crepe kraft paper-fiberglass reinforcing cloth-primary crepe kraft paper to be applied to each side of the bimetallic core is put through a laminating process wherein hot asphalt (laminating grade, as before) is applied to one side of each of the two sheets of primary crepe kraft paper and the coated sides of such paper brought into contact with and about the fiberglass reinforcing cloth under pressure. In the next step of this process, the bimetallic core is coated on both sides with a hot asphaltic composition and brought under pressure in a laminating machine between the two outer sandwiches prepared in the first step described above. The resulting product is that illustrated in FIG. 4.

The structure of FIG. 4, while providing many of the advantages of the flashing materials described above in the embodiments of FIGS. l-3, is an extremely tough and durable waterproofing material which will provide long-lasting and effective protection against the elements. It is slightly more expensive to fabricate than the materials of FIGS. 2 and 3 but less expensive than that of FIG. l.

Quite obviously, many variations man be made in the specific waterproofing materials which can be fabricated in accordance with the present invention while not detracting from the essential inventive concepts described above.

The articles coming within the framework of the present invention provide numerous significant advantages over comparable products of the prior art. For example, as compared with similar all-copper core products in which a comparable weight of copper is substituted for an equivalent weight of the lead-copper core of the present invention, the instant products are less expensive to fabricate and, in exposed applications, the lead side of the bimetal sheet of the present invention can be exposed without loss of life while retaining the non-staining quality of plain lead. As compared with a conventional laminated core containing lead laminated to copper by means of an asphaltic compound or the like, the structures of the present invention provide innumerable advantages, including but not restricted to the facts that (l) the present products are simpler and less expensive to manufacture, (2) the bimetal sheets of the present invention cannot be delaminated as is the case with the asphalt-bonded lead-copper sheets, (3) the finished multi-lamina products of the present invention are not as thick as prior art products providing comparable protection, thus permitting better control of mortar joints, etc.

But still additional advantages can be added to the list set forth above. For example, the present invention makes possible the convenient and effective fabrication of a structure such as that shown in FIG. 2, in which a fiberglass reinforcing cloth is bonded to a bimetallic core by passing both the reinforcing cloth and the core through a hot asphaltic bath (as described above) and then bringing the two together under pressure. Such a procedure could not be performed with prior art structures in which a sheet of lead was bonded to a sheet of copper by means of an asphaltic composition, since were the latter to be passed through a bath of hot asphalt, the lead-copper would delaminate as a result of the asphaltic bond between them.

Another significant advantage made possible by the present invention has to do with practical aspects of waterproofing material fabrication. Rolled lead sheets are generally commercially available in varying thickness but only in maximum sheet width of approximately 2l inches. Thus, to end up with a finished product width of approximately 60, three sheets of lead lapped in the direction of the length of the sheet would be required. To fabricate the desired l60" finished product, a single sheet of copper, ordinarily in `61" width, has a laminating grade asphalt applied t0 one of its surfaces and the three 21" wide lead sheets are fed into contact with and on top of the asphaltcoated copper sheet and placed under pressure. The resulting composite sheet is approximately 61" wide and contains raised ridge lines at the points of lapping of the lead sheets. This composite sheet may then be further processed to apply additional lamina on either or both sides of the composite as desired. Finally, the product may be trimmed to the desired 60 width in a conventional manner.

This process of laminating sheet lead to copper also presents a further problem. Because of the requirement of lapping the three sheets of 2l wide lead over the 61" wide copper sheet, and since there is at most only about 2 of lead available for such lapping, it is extremely difficult and impracticable to maintain consistent lapping due to straying of the three lead sheets, thus creating voids of lead and leaving the thin copper Sheet bare of lead at such voids.

By means of the process of the present invention, on the other hand, sheet copper, which is available in widths up to 64" wide, is coated completely and in -a continuous process to form a uniform and smooth lead coating of the desired thickness. As will be apparent, `the requirement for plural sheets as in the conventional process, not to mention the presence of undesirable ridge lines in the finished product, is eliminated by means of the present invention.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein,

What is claimed is:

1. A waterproofing material comprised of at least one bimetallic sheet formed of copper having a coating of electrodeposited lead on only one of its copper faces, an additional sheet of non-metallic material disposed 0n at least one of the faces of said bimetallic sheet, and an asphaltic composition bonding said additional sheet of material to said bimetallic sheet.

2. The material of claim 1 wherein said additional sheet of material is an asphaltic cotton fabric.

3. The material of claim 1 wherein said additional sheet of material is a fiberglass cloth.

4. The material of claim 1 further comprising at least one further additional sheet of material extending over said additional sheet of material, each succeeding sheet of material .being bonded to its adjacent sheet by said asphaltic composition.

5. The material of claim 1 wherein said copper is electrolytic sheet Copper.

6. A method of making a waterproong material comprising the steps of electrodepositing lead on only one face of a sheet of copper to form a bimetallic sheet, and bonding an additional sheet of non-metallic material on at least one of the faces of said bimetallic sheet by means of an asphaltic composition.

7. The method of claim 6 wherein said sheets are bonded by applying a hot asphaltic composition to at least one of the sheets, and laminating said sheets together.

8. The method of claim 6 further comprising the steps of bonding at least one further additional sheet of material to said additional sheet of material, each succeeding sheet of material being bonded to its adjacent sheet by said asphaltic composition.

9. The method of claim 8 wherein said sheets are bonded by applying a hot asphaltic composition to at least one of the sheets, and laminating Said sheets together.

10. The method of claim 6 wherein said copper sheet is electrolytically formed.

References Cited v UNITED STATES PATENTS 9/1924 Dana 204-32 4/1960 Lancy 204-206 OTHER REFERENCES Catalog Sheet, Revere Copper and Brass, Inc., 230 Park Ave., New York, N.Y. Printed December 1953, 2 pages.

HAROLD ANSHER, Primary Examiner C. B. COSBY, Assistant Examiner U.S. Cl. X.R. 

